US3770940A - Optical bar coding scanning apparatus - Google Patents

Optical bar coding scanning apparatus Download PDF

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US3770940A
US3770940A US00198331A US3770940DA US3770940A US 3770940 A US3770940 A US 3770940A US 00198331 A US00198331 A US 00198331A US 3770940D A US3770940D A US 3770940DA US 3770940 A US3770940 A US 3770940A
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circuit
terminals
sector
output terminals
scanning apparatus
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J Harr
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International Business Machines Corp
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International Business Machines Corp
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    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
    • G06K7/10—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
    • G06K7/10544—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation by scanning of the records by radiation in the optical part of the electromagnetic spectrum
    • G06K7/10821—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation by scanning of the records by radiation in the optical part of the electromagnetic spectrum further details of bar or optical code scanning devices
    • G06K7/10881—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation by scanning of the records by radiation in the optical part of the electromagnetic spectrum further details of bar or optical code scanning devices constructional details of hand-held scanners

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  • ABSTRACT The scanning of documents bearing optical bar coding, particularly with hand-held scanning apparatus. is enhanced by an optical system effecting an elongated aperture substantially parallel to the bars without constriction as to the orientation of the apparatus.
  • Corelated configurations of light sources, light sensitive devices, aperture plates and/or prisms are arranged with one or more effectively rotating under control of electronic circuitry for viewing the bars at a multiple of angular positions is disclosed.
  • a photosensitive diode arrangement of substantially circular configuration is divided into a multiple of radially extending sectors isolated from each other, and diametrically collinear sectors are connected together as sector-couples.
  • Electronic circuitry determines the sector-couple having the minimum response and selects that couple for the completion of the scanning operation or until disorientation dictates another selection.
  • Another embodiment comprises a circular photosensitive section insulated from the sectors and located centrally of the sector couples. ln this embodiment the photosensitive section is connected to the chosen sector couple for improved resolution.
  • Electronic multiplexing circuitry, signal peak predicting circuitry, rate of rise comparing circuitry, single sectorcouple selecting circuitry and other pertinent electronic circuitry are described.
  • PATENTEDHDV 8 I975 SHEET MARK MARK PROC 4 DH 30 CIRCUIT j CIRCUIT STROBE OUT PATENTEBnuv s 1975 SHEET 070F 14 PATENTEU IIUV 6 I975 SHEET IUUF 14 F
  • the invention relates to optical scanning apparatus for sensing information recorded in a series of vertical lines or bars substantially parallel to each other, and it particularly pertains to hand-held optical scanning ap' paratus and/or machine scanning apparatus of extremely loose tolerances in either or both the machine and/or the recording of the bars on the document being scanned.
  • the size and shape of the photosensitive area effective in sensing the information has a large effect on the reliability and the usability of the system.
  • the sensing area is large and a large signal-to-noise ratio obtains.
  • that rectangular area must be aligned with the marks to be sensed. This is a difficult task for the operator of a manual scanning apparatus and the same problems are present to a degree in machine scanning apparatus.
  • Photosensitive devices with circular configurations have been suggested. These configurations are free from from orientation problems but the signal-tonoise ratio suffers due to the small area and reliability is likewise low.
  • a basic concept of the invention comprises an optical system providing a rotating optical pupil resulting from an elongated optical aperture stop which is dimensionally proportional to the bars of the coding.
  • Light from a suitable source is transmitted to a suitable photosensitive device by reflection from the document bearing printed coding bars.
  • a rotating aperture disk is interposed between the light source and the document and in another the rotating disk is interposed between the photosensitive device and the document being scanned by passing the optical system relatively along the coding orthagonally of the bars.
  • the aperture disk is fixed and rotation of the pupil is effected by a mechanically rotating Dove prism interposed in the optical system.
  • Still other embodiments comprise an optical fiber bundle having one end of elongated configuration constituting the optical aperture stop and the other end in any, but preferably in a circular, configuration for coupling to the source of light or the photosensitive device.
  • This optical fiber bundle is rotated about an axis normal to the plane of and centrally of the elongated aperture stop.
  • Suitable means for mechanically rotating the mecha nisms are known and readily available and the rotation is synchronized in the scanning operation so that the optimum alignment of the effective or actual aperture obtains at the times the bar coding is sensed during the scanning operation.
  • Suitable means for such synchronized operation are linear and readily available.
  • Rotation of an effective optical pupil is obtained in an alternative embodiment wherein an optical fiber bundle is separated in substantially radially extending sectors at the larger end and a multiple of light sources such as light emitting diodes, are sequentially switched on to illuminate the document in collinear pairs of sectors.
  • a multiple of light sources such as light emitting diodes
  • the light source is shaped to constitute the aperture stop (as in the lens of some optical systems for the simple photographic cameras).
  • a source comprises a sectored light emitting device of the nature of a semiconductor. Diametrically collinear sectors are energized sequentially for light wavelength emission. Much faster rotation of the pupil is possible with the latter structures but the quantity of light available with conventional materials is not as great as is desired.
  • a sectored photosensitive device is arranged in an optical scanning system like those described above.
  • Conventional materials and methods of manufacture provide a highly satisfactory device at reasonable cost.
  • the sectored photosensitive device according to the invention is substantially fixed from the rotational standpoint and the diametrically collinear sectors of configuration constituting the aperture stop are con nected together electrically to form sector'creples.
  • a central photo sensitive section of the array is electrically isolated from the sectors but functionally coupled in operation for improving the operation of one or all sectorcouples.
  • the photosensitive sector-couple most nearly aligned with the bars is selected for sensing in normal manner with or without inclusion of the central photosensitive section.
  • electronic circuitry is arranged for determining the alignment of at least the most nearly aligned sector-couple and for switching sector couples automatically.
  • a simple electronic arrangement comprises an analog OR gating circuit connecting all sector-couples to an operational amplifying circuit.
  • a more elaborate embodiment of this circuit arrangement comprises a peak signal clamping circuit and a peak signal storing circuit connected in cascade between each sector-couple and a multiple transistor selection gating circuit in which only the transistor connected to the storage circuit having the highest peak value conducts.
  • More complex circuitry comprises parallel and serial multiplexing of sectorcouples in a continuing sampling mode of operation. These arrangements continuously compare the output of a selected sector-couple with outputs of all other sector-couples and automatically switch to the most nearly aligned sector-couple. Efficient arrangements for different applications are based on slope detection circuitry determining the rate-of-rise of input voltage waves for switching from one sector-couple to a different one.
  • FIGS. 1 and 2 are graphical representations of two forms of optical bar coding for which apparatus according to the invention is intended to sense;
  • FIG. 3 illustrates the use of a rotating elongated aperture stop in an optical system for scanning bar coding
  • FIGS. 4-8 are schematic diagrams of fundamental optical bar coding scanning apparatus according to the invention.
  • FIG. 9 is a schematic functional diagram of electronic bar coding scanning apparatus according to the invention.
  • FIGS. 10 and 11 are illustrations of a photosensitive device according to the invention.
  • FIG. 12 depicts a sectored photosensitive device according to the invention as optically imaged onto printed coding bars of a document
  • FIGS. 13 and 14 are graphical representations of two different sets of bars and electric waveforms resulting from scanning these bars;
  • FIG. 15 is a functional diagram of circuitry for analyzing the electric waves obtained from a photosensitive device according to the invention.
  • FIG. 16 is a schematic diagram of circuitry used with the photosensitive array according to the invention.
  • FIG. 17 is a schematic diagram of a photosensitive device amplifier according to the invention.
  • FIG. 18 is a schematic diagram of photosensitive device selection and gating circuitry
  • FIG. 19 is a graphical representation of a photosensitive array according to the invention, optical scanning marks, and waveforms resulting from the scanning of these marks;
  • FIG. 20 is a functional diagram of a multiplexing circuitry according to the invention.
  • FIG. 21 is a schematic diagram of a mark detecting circuit according to the invention.
  • FIG. 22 is a graphical representation of waveforms obtained with the mark detecting circuit of FIG. 21;
  • FIG. 23 is a graphical representation of the alignment of a photosensitive device according to the invention and optical bars or marks;
  • FIG. 24 is a functional diagram of a circuitry for use with the photosensitive scanning array according to the invention.
  • FIG. 25 is a graphical representation of waveforms obtained with the circuitry of FIG. 24;
  • FIG. 26 is a schematic diagram of a detecting circuit according to the invention.
  • FIG. 27 is a graphical representation of the operation of a portion of the circuitry of FIG. 26;
  • FIG. 28 is a graphical representation of a photosensitive device according to the invention and optical marks, and waveforms resulting from the scanning of that mark by that device;
  • FIG. 29 is a graphical representation of a basic detec tion scheme according to the invention.
  • FIG. 30 is a schematic diagram of a slope detecting circuit according to the invention.
  • FIG. 31 is a graphical representation of waveforms obtained in the operation of the slope detecting circuitry of FIG. 30;
  • FIG. 32 is a functional diagram of peak predicting circuitry according to the invention.
  • FIG. 33 is a graphical representation of waveforms obtained in the operation of the peak-predicting circuitry of FIG. 32;
  • FIG. 35 is a graphical representation of waveforms obtained with the circuitry of FIG. 34;
  • FIG. 37 is a graphical representation of waveforms obtained with the circuitry of FIG. 36.
  • FIGS. I and 2 Two examples of bar coding for which the scanning apparatus according to the invention was developed are shown in FIGS. I and 2, but it should be clearly understood that the apparatus according to the invention is equally adaptable to almost all, if not all, other bar coding arrangements, since those skilled in the art will readily adapt the teachings herein to the particular bar coding scheme at hand.
  • FIG. 1 illustrates the underly ing principle of RPM (retrospective pulse modulation) bar coding as described and claimed in the copending U.S. Pat. application Ser. No. 31,959 hereiizbeforc mentioned.
  • Information in the form of a 12 ordm binary number, IOIOOOIOIOII is coded in this general example.
  • a series of parallel lines 3952 are arranged for conversion into a train of narrow electric pulses by photosensitive apparatus according to the invention.
  • the data is established at time intervals proportional to the spacing between the lines 39-52.
  • a start line or bar 39 is followed at a predetermined spacing by a reference bar 40 for initiating the retrospective coding.
  • the first information manifesting bar 41 follows a reference 40 by a spacing substantially equal to the spacing between the start bar 39 and the reference bar 40 to manifest a binary unit; obviously a binary naught might better be manifested by this arrangement depending upon the situation facing the designer.
  • the following bar 42 is arranged on the former basis to denote a binary naught by spacing the bar 42 substantially twice the distance from the preceding bar 41 as that bar follows the reference bar 40.
  • the information is carried essentially by the spacing between bars. Accordingly there is illustrated an example of each of the possibilities of data manifestation in basic binary digit RPM coding where the immediate preceding spacing is reflected in the spacing of the digit under consideration.
  • FIG. 2 the same binary data is manifested by the transistions between highly contrasted white and black areas.
  • Apparatus according to the invention is passed over this transition-significant form of RPM bar coding from a point before the starting edge 39 to a point beyond the final edge 52'.
  • An electric pulse signal is developed at each transition from white to black and again from black to white.
  • Preferably a differentiating process is involved in either case.
  • Each differential pulse is significant with respect to data in the transition significant form whereas alternate pulses are not in the basic example. This difference is of immediate importance in increasing the density of the coded data and in the elimination of superfluous pulses in the data signal which may interfere as though spurious.
  • FlG. 3 illustrates the basic problem.
  • Three bars 54, 56, and 58 in typical configuration are recorded on a document.
  • An aperture stop plate 60 having an elongated rectangular aperture 62 forms a basic part of the scanning apparatus.
  • the aperture 62 is proportional to the bars to be sensed.
  • the plate 60 is used in this illustration for better contrasting the pupil from the bars and is shown skewed with respect to the bars 54-58 for emphasizing the difficulty with prior art arrangements.
  • the aperture plate 60 is rotated at a predetermined rate of rotation much faster than the rate of scan.
  • the arrangement preferably is further disposed so that the photosensitive device is exposed to light passing through the aperture stop 62 only at those two particular angles plus or minus a small angular tolerance.
  • FIG. 4 There are several embodiments of this basic concept.
  • a document 64 is moved relatively slowly beneath the aperture stop plate 60 shown in cross section to expose the bars 54' and 56' illuminated by a light source 66 in an optical system also comprising a lens 68 and a photosensitive device 70.
  • this schematic showing means for rotating the aperture plate 60 and keying the response of the photosensitive device 70 are omitted in the interest of clarity.
  • Known arrangements will be immediately suggested to those skilled in the art for the application at hand.
  • FIG. 5 A dual of the latter arrangement is shown in FIG. 5 wherein the light source 66 is arranged to illuminate the aperture stop 62 and a photosensitive device is arranged to receive light reflected from the background of and the marks on the document 64.
  • FIG. 5 A slightly different arrangement is shown in FIG.
  • FIG. 7 Another embodiment having a mechanically rotating element is shown in FIG. 7.
  • a bundle of optical fibers 70 are arranged to have a circular configuration at the end adjacent the light source 66 and a propeller-shaped configuration defining the aperture stop at the end adjacent the document 64. Again synchronizing the rotating means to the detec tion circuitry is contemplated as comprising conventional system components.
  • FIG. 8 illustrates a system in which a light source 80 is sectored into narrow substantially triangular segments the outlines of which define the aperture stop. These segements are energized in diametrically collinear pairs for illuminating the document 64 in essentially the same manner as the arrangement of FIG. 7.
  • the sectored light source 80 may be an array of light emitting diodes of differing diameters from the center of the device and interconnected groups forming the pie-shaped sectors described.
  • light emitting diode devices are readily formed in pie-shaped sector configuration. Such a configuration is suggested by a component in FIG. 9.
  • An alternative embodiment is contemplated in the form of an optical fiber bundle of circular cross-section at the ends separated into a number of substantially radially extending sectors each pair similar to the bundle 70 in FIG. 7 at the larger end and a multiple of light sourtms such as light emitting diodes are sequentially switched on to illuminate the document in collinear pairs of sectors. Thus rotation is effected at electric and/or optic rates.
  • the photoresponsive device 90 as shown is a substantially circular photocell arrangement having 16 equal sectors A, B, G, H and a, b, g, and h laid down on a substrate in conventional manner. No further description will be given of the construction of such a device as the fabrication in and of itself is not a part of the invention.
  • a backing electrode is common to all of the sectors and is arranged with an electric lead for connection to a point of reference potential which is shown in this illustration a being at ground potential.
  • the sectors are insulated from each other and are connected in diametrically collinear pairs or couples as Aa, Bb I-Ih.
  • the sector-couples are connected to a couple-selecting switching circuit arrangement 92 and also to a couplealignment detecting circuit arrangment 94.
  • the sectorcouples are selected sequentially, for example, at the beginining of a scanning operation and the couple alighment detecting circuit arrangment 94 determines which couple receives the minimum amount of light when centered over a mark, (or maximum light when centered over clear space) as this indicates the closest sector-couple aligned with the marks.
  • the couple alignment detector circuit arrangement then fixes the couple-selecting switch on that particular sector-couple for operation for the remainder of the scan and light output levels are delivered at output terminals 96 and 98. Arrangements for operating one or more of the components in parallel also will be described hereinafter.
  • the layout diagram of sector photosensitive device as actually constructed is shown in FIG. 10.
  • the device 100 comprises 32 sectors arranged at angles of approximately 1 I25".
  • This arrangement there is also a central photosensitive section U which is insulated from all of the other sections A-h.
  • One sector couple Aa and the central section U are shown separated from the remainder of the array in FIG. 11.
  • the sector couples are electronically time division multiplexed, or otherwise operated, so that the result is a scanner which acts very much like the mechanical scanners described hereinbefore.
  • Other configurations of sector-couples in arrays are shown and described in a later filed copending U.S. patent application, Ser. No. 225,895, filed on the 14th day of Feb., 1972, of David Harwood McMurtry for "Optical Bar Coding Scanning Device.”
  • Flg. 12 shows a sectored photosensitive device 110 with the marks 111 116 ofa document optically imaged thereon. As shown, the photosensitive device 110 is centered on the central mark 114.
  • the sector-couple Aa receives the minimum amount of light
  • the sector-couple Jj cross-angled to the axis of the marks receives an amount of light which is an average in the direction of scan and which depends on the average mark-to-space ratio of the three or four marks in each direction from the center.
  • FIGS. 13 and 14 show two different sets of bars and the electric waveforms resulting from scanning these bars as the photosensitive array is "rotating rapidly as it is moved along.
  • Relatively wide bars 121, 122 and 123 produce a trace 124.
  • An analysis of this trace 124 results in one wave 126 representing negative peak voltage a wave 127 representing positive peak voltage and wave 128 representing the sum of these peak voltage waves.
  • Relatively narrow bars 131, 132 and 133 have the same repetition rate spacing developed in a trace 134 and corresponding analytical waves 136, 137 and 138. From these curves it can be seen that the difference in output from the dark level to the average level in FIG.
  • FIG. 13(b) is much smaller than the output level from the average to the light level, while the converse is true in FIG. 14(b). Circuitry for producing these analytical waves is shown in FIG. 15.
  • the output of the scanning detecting device is applied at input terminals 140.
  • a positive peak follower circuit 142 and a negative peak follower circuit 144 are connected to the input termals for producing the peak level voltages which are in turn applied to a summing circuit 146 at the output terminals 148 of which the algebraic sum of the instantaneous amplitudes is obtained.
  • the summed outputs of the peak follower circuits 142 and 144 contains all the information required to detect the bars and is of relatively constant amplitude as can be seen by examining curves 128 and 138 of FIG. 13(b) and FIG. 14(b).
  • FIG. 16 illustrates circuitry for obtaining the peak outputs by operation of all of the photoresponsive sec tor-couples simultaneously. Only a few of the sectorcouples of a sectored photosensitive device 150 are shown in the interest of clarity. In conventional photoresponsive devices the output voltages are usually not higher than the diode forward resistance drops; hence the use of amplifying circuits 154 157 is contemplated. An example of a suitable amplifying circuit 154' is shown in FIG. 17. A sector couple is represented by a photo diode 160 which is reversed-biased and oper ated as a current source.
  • a transistor 162 and a load resistor 164 are connected in a common base amplifying circuit providing high output voltage and a following transistor 166 and associated emitter resistor 168 are arranged to provide a low impedance drive through the subsequent peak following circuits.
  • the peak following circuits comprise diodes 174 177 a resistor 178 connected as shown to a positive peak output terminal 180 and oppositely poled diodes 184 187 and another resistor 188 connected as shown to negative peak value output terminals 190. The operation of circuit arrangement will be described on the basis of the voltages indicated on the drawing.
  • the positive peak follower output will be drawn up to the highest input voltage, that is 15 volts.
  • the negative peak follower circuit output will follow the lowest sector-couple output which is shown as 5 volts.
  • the advantage of this circuit arrangement is that the highest frequency of interest is now the same as the bandwidth of the photosensitive sector-couple rather than the several megaHertz required in a multiplexing scheme. Consequently the amplifying circuits are simpler and the noise level is lower.
  • Another arrangement for obtaining a usable analog signal is simply to examine the output voltages of all sector-couples and determine which couple has the largest peak-topeak signal swing. This couple is then the one which is most closely aligned with the bars. Circuitry is then arranged to switch this pair to the analog output terminals for bar detection and processing.
  • FIG. 18 Such an arrangement is shown in FIG. 18.
  • the photosensitive sector-couple signals are applied to peak clamping circuits 191 which clamp the most negative portion of the waveforms to a oin of fixed reference potential, shown here as grout.
  • tan tial Following this is a peak storing circuit 192 which develops a direct voltage output equal to the peak-t0- peak signal swing from the input signal.
  • the output of each peak storing circuit connected to the base of a transistor 194, 195 and so on.
  • the emitter electrodes of all of the transistors are connected together. Whichever peak storing circuit has the highest output causes the associated transistor to conduct (all of the other transistors will remain blocked).
  • the collector eleerodes of the transistors are connected (level shifting circuits 196 and 197 may be necessary.) to switching transistors 204 and 205 and so forth for connecting the photosensitive sector-couple having the highest output to the analog output terminals to 206.
  • a center photosensitive section offers advantages. A difficulty is encountered, however, whenever the center photosensitive section is approaching the group of data bars.
  • circuitry as shown in FIG. 16 in the center section, is coupled through an amplifying circuit 208 to output terminals 210. These output terminals along with output terminals 180 and 190 coupled by means of resistors 212, 214 and 216 to a summing circuit 218 at the output terminals 220 of which the sums of all the components are provided.
  • the output of the positive peak following circuit at the terminals 180 increases and consequently so does the sum output.
  • FIG. 19(a) three data bars 221, 222 and 223 are approached by a photosensitive scanning device 230 according to the invention.
  • the corresponding trace 232 is shown in FIG. 19(b). From this figure it is seen that the leading edge of the first bit is inaccurately located using just the sum information. This difficulty appears whenever the average darkness over the photosensitive device changes faster than the darkness of the bars under the center of the photosensitive device. While this problem might be circumvented by always having marks present, this would mean that preceding and following valid data there would be continuous space for no code data (appearing whereever data is not practically represented). Many bar code arrangements involve a start character as the first character of data. In such arrangements the first mark in this character is made longer than the following space. This apparent stretching of the initial mark will have no effect on the data recovery. According to the invention the information provided by the center photosensitive section is arranged to herald the entry of the mark or bar into the array center. The output of the center photosensitive section is represented in FIG. 19(d).
  • the output of the peak summing circuit 146 at terminals 148 is applied to a slope detecting circuit 244.
  • This slope detecting circuit 244 has one output terminal active during a positive going input and the other active during a negative going input. The two inputs would be complementary except for a built-in hysteresis which provides noise immunity for the circuit. An example of such a slope-detecting circuit will be given hereinafter.
  • curves 234, 236, and 238 represent the negative peak output envelope, the positive peak envelope, and the sum of the two respectively in the same manner for th earlier examples.
  • the two outputs of the slope detecting circuit 244 are applied to the set and reset terminals of a latching bilateral reciproconductive circuit 246.
  • reciproconductive circuit is construed to include all dual current flow path element (including vacuum tubes, transistors and other current flow controlling devices) regenerative circuit arrangements in which current flow alternates in one and then the other of those elements in response to applied triggering pulses.
  • the term free running multivibrator is sometimes applied to the astable reciproconductive circuit" which is one in which conduction continuously alternates between the elements after the application of a single triggering pulse (which may be merely a single electric impulse resulting from clos' ing a switch for energizing the circuit).
  • a single triggering pulse which may be merely a single electric impulse resulting from clos' ing a switch for energizing the circuit.
  • SUch a circuit oscillates continuously at a rate dependent on the time constants of various components of the circuit arrangement and/or the applied energizing voltage.
  • monostable reciproconductive circuit will be used to indicate such a circuit as the time delay circuit in which a single trigger is applied to a single input terminal to trigger the reciproconductive circuit to the unstable or operating state once and return to the stable or idling state.
  • bistable reciproconductive circuits are divided into two basic circuits.
  • One is the bistable reciproconductive circuit having two input terminals between which successive triggers must be alternately applied to switch from one stable state to the other, will be referred to as a bilateral reciproconductive circuit.
  • these stable states are distinguished as "set” and reset states, the latter frequently being an idling state.
  • This version is loosely called both a flip-flop" and a lockover circuit.”
  • the other is the binary reciproconductive circuit which has one iriput terminal to which triggering pulses are applied to alternate the state of conduction each time a pulse is applied.
  • Another type of reciproconductive circuit comprises of several types frequently loosely referred to in the vernacular as Schmitt triggers. They differ from the previously mentioned circuits in that primarily in response to changes in level and restore to the initial state when the reciprocating level drops. This type of circuit will be referred to as a level triggering reciproconductive circuit or as a leveltriggering circuit. Such level triggering circuits are excellent for resolving the evaluation of singles in binary fashion.
  • the level triggering flip-flop When the signal level is sufficient to be recognized the level triggering flip-flop will switch to a state so indicating.
  • These circuits exhibit an hysteresis characteristic which is an advantage in more clearly section output must be increasing in order to indicate distinguishing levels, such as obtained with light sensing apparatus, having intermediate values that reflect marginal operation; only the signal definitely desired for operation will switch the circuit designed for the applications and hold it until the signal level has dropped well below the trigger level.
  • the transition of the output of the reciproconductive circuit 246 correspond to the edges of the bar. This output would be all that would be necessary from the mark detector circuitry if additional circuitry were not to be added to aid in detecting the leading edge of the first bar.
  • the center photosensitive section U is connected to the terminals 210' leading to a slope detecting sircuit 254 of similar construction to that of slope detecting circuit 244. In the same manner the output of the slope detecting circuit 254 is applied to another

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US00198331A 1971-11-12 1971-11-12 Optical bar coding scanning apparatus Expired - Lifetime US3770940A (en)

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Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3993888A (en) * 1974-10-29 1976-11-23 Calspan Corporation Scanning line filter
US4300170A (en) * 1977-08-19 1981-11-10 Dainippon Screen Seizo Kabushiki Kaisha Picture outline tracing and recording machine
US4376582A (en) * 1980-12-09 1983-03-15 The United States Of America As Represented By The United States Department Of Energy Optical fuel pin scanner
US4411528A (en) * 1981-01-19 1983-10-25 Control Data Corporation Optical displacement and contour measuring
US4465374A (en) * 1979-02-27 1984-08-14 Diffracto Ltd. Method and apparatus for determining dimensional information concerning an object
US4493989A (en) * 1982-04-28 1985-01-15 Hampson Alfred A Container end-code redemption scanning
US4637718A (en) * 1980-12-09 1987-01-20 The United States Of America As Represented By The United States Department Of Energy Hand-held optical fuel pin scanner
US4710615A (en) * 1986-06-26 1987-12-01 Ncr Corporation CCD bar code scanner
US5124538A (en) * 1988-08-26 1992-06-23 Accu-Sort Systems, Inc. Scanner
US5528023A (en) * 1992-10-09 1996-06-18 Johnson & Johnson Clinical Diagnostics, Inc. Bar code detecting circuitry
US5548107A (en) * 1988-08-26 1996-08-20 Accu-Sort Systems, Inc. Scanner for reconstructing optical codes from a plurality of code fragments
US5744795A (en) * 1995-07-31 1998-04-28 Hewlett-Packard Company Illumination strobing in a scanner to improve image sharpness and power consumption
US20040011871A1 (en) * 2001-07-30 2004-01-22 Harper Jerry D. Object identification using an optical scanner

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5326623A (en) * 1976-08-25 1978-03-11 Mitsubishi Electric Corp Bar-code label reading device
JPS5452422A (en) * 1977-10-03 1979-04-25 Sharp Corp Bar-code reader
EP0233888B1 (de) * 1984-12-14 1990-12-12 AHLBOM, Sten Hugo Nils Anordnung zur behandlung von bildern
JPH02183879A (ja) * 1989-01-10 1990-07-18 Sumitomo Electric Ind Ltd バーコードリーダ
JP2788152B2 (ja) * 1992-06-22 1998-08-20 松下電器産業株式会社 バーコードリーダ
US6229964B1 (en) * 1998-02-26 2001-05-08 Eastman Kodak Company Image with sound playback apparatus

Citations (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2568543A (en) * 1949-08-03 1951-09-18 Rca Corp Automatic registration of component color images
US3061730A (en) * 1960-10-19 1962-10-30 Barnes Eng Co High resolution tracker
US3246126A (en) * 1960-11-02 1966-04-12 Sylvania Electric Prod Data processing
US3255437A (en) * 1961-01-23 1966-06-07 John W Ralls Electronic recognition
US3414731A (en) * 1966-10-28 1968-12-03 Sylvania Electric Prod Package classification by tracking the path of a circular label and simultaneously scanning the information on the label
US3418456A (en) * 1966-12-14 1968-12-24 Monarch Marking Systems Inc Encoded tag reader
US3453596A (en) * 1965-03-29 1969-07-01 Sperry Rand Corp Pattern recognition apparatus
US3465130A (en) * 1965-08-30 1969-09-02 Rca Corp Reliability check circuit for optical reader
US3497704A (en) * 1966-06-08 1970-02-24 Cornell Aeronautical Labor Inc Automatic photo-culture detection system for determining the presence and location of low curvature objects in photographic data
US3506837A (en) * 1965-12-15 1970-04-14 Hitachi Ltd Pattern-detecting device using series connected photosensitive bodies
US3522437A (en) * 1964-12-03 1970-08-04 Farrington Electronics Inc Reading apparatus for two or more different size type fonts
US3553437A (en) * 1967-05-02 1971-01-05 Sylvania Electric Prod Optical label reading system and apparatus
US3596063A (en) * 1969-01-13 1971-07-27 Ibm Apparatus for reading marks on documents
US3596060A (en) * 1967-05-04 1971-07-27 Alexander Inc Optical scanning unit for mark sensing
US3636317A (en) * 1969-04-28 1972-01-18 Charecogn Systems Inc Machine readable code track
US3643068A (en) * 1969-03-12 1972-02-15 Spartanics Random oriented decoder for label decoding

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3416152A (en) * 1964-04-22 1968-12-10 Theodore R. Trilling Analog-to-digital converter
US3553438A (en) * 1969-07-18 1971-01-05 Sylvania Electric Prod Mark sensing system

Patent Citations (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2568543A (en) * 1949-08-03 1951-09-18 Rca Corp Automatic registration of component color images
US3061730A (en) * 1960-10-19 1962-10-30 Barnes Eng Co High resolution tracker
US3246126A (en) * 1960-11-02 1966-04-12 Sylvania Electric Prod Data processing
US3255437A (en) * 1961-01-23 1966-06-07 John W Ralls Electronic recognition
US3522437A (en) * 1964-12-03 1970-08-04 Farrington Electronics Inc Reading apparatus for two or more different size type fonts
US3453596A (en) * 1965-03-29 1969-07-01 Sperry Rand Corp Pattern recognition apparatus
US3465130A (en) * 1965-08-30 1969-09-02 Rca Corp Reliability check circuit for optical reader
US3506837A (en) * 1965-12-15 1970-04-14 Hitachi Ltd Pattern-detecting device using series connected photosensitive bodies
US3497704A (en) * 1966-06-08 1970-02-24 Cornell Aeronautical Labor Inc Automatic photo-culture detection system for determining the presence and location of low curvature objects in photographic data
US3414731A (en) * 1966-10-28 1968-12-03 Sylvania Electric Prod Package classification by tracking the path of a circular label and simultaneously scanning the information on the label
US3418456A (en) * 1966-12-14 1968-12-24 Monarch Marking Systems Inc Encoded tag reader
US3553437A (en) * 1967-05-02 1971-01-05 Sylvania Electric Prod Optical label reading system and apparatus
US3596060A (en) * 1967-05-04 1971-07-27 Alexander Inc Optical scanning unit for mark sensing
US3596063A (en) * 1969-01-13 1971-07-27 Ibm Apparatus for reading marks on documents
US3643068A (en) * 1969-03-12 1972-02-15 Spartanics Random oriented decoder for label decoding
US3636317A (en) * 1969-04-28 1972-01-18 Charecogn Systems Inc Machine readable code track

Cited By (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3993888A (en) * 1974-10-29 1976-11-23 Calspan Corporation Scanning line filter
US4300170A (en) * 1977-08-19 1981-11-10 Dainippon Screen Seizo Kabushiki Kaisha Picture outline tracing and recording machine
US4498109A (en) * 1977-08-19 1985-02-05 Dainippon Screen Seizo Kabushiki Kaisha Picture outline tracing and recording machine
US4465374A (en) * 1979-02-27 1984-08-14 Diffracto Ltd. Method and apparatus for determining dimensional information concerning an object
US4376582A (en) * 1980-12-09 1983-03-15 The United States Of America As Represented By The United States Department Of Energy Optical fuel pin scanner
US4637718A (en) * 1980-12-09 1987-01-20 The United States Of America As Represented By The United States Department Of Energy Hand-held optical fuel pin scanner
US4411528A (en) * 1981-01-19 1983-10-25 Control Data Corporation Optical displacement and contour measuring
US4493989A (en) * 1982-04-28 1985-01-15 Hampson Alfred A Container end-code redemption scanning
US4710615A (en) * 1986-06-26 1987-12-01 Ncr Corporation CCD bar code scanner
US5466921A (en) * 1988-08-26 1995-11-14 Accu-Sort Systems, Inc. Scanner to combine partial fragments of a complete code
US5124538A (en) * 1988-08-26 1992-06-23 Accu-Sort Systems, Inc. Scanner
US5548107A (en) * 1988-08-26 1996-08-20 Accu-Sort Systems, Inc. Scanner for reconstructing optical codes from a plurality of code fragments
US6206289B1 (en) 1988-08-26 2001-03-27 Accu-Sort Systems, Inc. Scanner
US6669091B2 (en) 1988-08-26 2003-12-30 Accu-Sort Systems, Inc. Scanner for and method of repetitively scanning a coded symbology
US20040182931A1 (en) * 1988-08-26 2004-09-23 Charles Lapinski Method for assembling fragments of scanned data
US7000838B2 (en) 1988-08-26 2006-02-21 Accu-Sort Systems, Inc. Method for assembling fragments of scanned data
US5528023A (en) * 1992-10-09 1996-06-18 Johnson & Johnson Clinical Diagnostics, Inc. Bar code detecting circuitry
US5744795A (en) * 1995-07-31 1998-04-28 Hewlett-Packard Company Illumination strobing in a scanner to improve image sharpness and power consumption
US20040011871A1 (en) * 2001-07-30 2004-01-22 Harper Jerry D. Object identification using an optical scanner
US6935564B2 (en) * 2001-07-30 2005-08-30 Bayer Healthcare Llc Circuit and method for correcting influence of AC coupling

Also Published As

Publication number Publication date
CA1012645A (en) 1977-06-21
FR2172662A6 (de) 1973-09-28
CA978277A (en) 1975-11-18
DE2305669B2 (de) 1975-06-19
DE2305669A1 (de) 1973-08-30
NL173448C (nl) 1984-01-16
JPS5315619B2 (de) 1978-05-26
DE2254863A1 (de) 1973-05-17
CH548068A (de) 1974-04-11
JPS4856344A (de) 1973-08-08
FR2159894A1 (de) 1973-06-22
NL173448B (nl) 1983-08-16
CH554021A (de) 1974-09-13
GB1404598A (en) 1975-09-03
DE2254863C3 (de) 1975-09-11
DE2254863B2 (de) 1975-02-06
NL7212701A (de) 1973-05-15
AU4851672A (en) 1974-05-09
US3770942A (en) 1973-11-06

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